This analysis retrospectively reviewed the data from all patients admitted with cardiac complications of thyrotoxicosis to a single New Zealand hospital between 1 January 2005 and 31 December 2012. Of 72 patients who were identified as being admitted for a cardiac complication of thyrotoxicosis, 32 were admitted because of dysrhythmia, 12 had ischaemia, 11 were in cardiac failure and 17 had mixed cardiac disease. Thyrotoxicosis was most commonly caused by Graves’ disease (n=25) and amiodarone (n=19). The cohort was over-represented by Māori (36.1% vs 16.8% of all cardiac admissions over the same period) and Māori were more likely to present with cardiac failure than non-Māori (57.7% vs 26.1%; p=0.008).